Use of Green Corrosion Inhibitors for Reinforced Concrete

Abstract

Concrete is the main element of construction material. To increase the durability and strength of construction, concrete is essentially used. However for the construction of mega structure Reinforced concrete is using. Corrosion is one of the major durability issues faced in the reinforced concrete. Study and protect the effect of corrosion, various techniques have been developed in which various types of inhibitors and coating were used for protection. Application of commercially available inhibitors are costly and hazardous in nature. Recent scenario is to make development of organic green corrosion inhibitor from agro-forest products. Green corrosion inhibitors can possibly a viable and economical solution for the corrosion issues of reinforcement in concrete. Various treatments are used to slow corrosion damage to metallic objects which are exposed to the weather, salt water, acids, or other hostile environments.

Corrosion causes destruction or deterioration of material due to reaction with environment. The destruction of the passivating layer occurs when the alkalinity of the concrete is reduced or when the chloride concentration in concrete is increased to a certain level. The effect of saline water on concrete is studied by prepared cube, cylinder and beam measured its compressive strength, tensile strength and flexural strength of the concrete respectively. Corrosion inhibitors are used to delay the rate of corrosion, Synthetic corrosion inhibitors are primarily developed from inorganic substances in which most of them contain heavy metals viz.arsenic, cadmium, chromium, cobalt, lead and zinc. Which are hazardous in nature, therefore Green corrosion inhibitors are of interest it has been an increase in environmental awareness and restrict usage of corrosion inhibitors due to their toxicity.

The study was to explore the possibility to use the extract of Cynodon dactylon (Bermuda Grass) and Azadirachta indica (Neem leaves) as a corrosion resistances. The efficiency and yield of these corrosion inhibitors are higher as well as environment friendly. Hot-reflux process and solvent process is used for extraction and make comparison of their yielding. Extract product is characterised by the Fourier transform infrared (FT-IR) and phenolic test. FT-IR result and phenolic test indicate as it improved the corrosion resistances. To assess the performance an accelerated corrosion test is to be performed on RC specimen which incorporates C.dactylon extract and Azadirachta indica as an inhibitors in RC specimens. To measured its mechanical properties rebound hammer test, Ultra Sonic Pulse Velocity Test is performed. Corrosion is to be monitor by corrosion monitoring techniques, i.e. half-cell potential and Resistivity meter. After performed accelerate corrosion test on RC specimen, performed Pull Out Test, and a comparison of its behaviour with corroded and uncorroded specimen is formulated.

Coating specimens is prepared with appropriate consistency of green corrosion extracts. The bond test is used to determine its adhesives bond strength. The corrosion resistance was increased by the addition of extracts. To measure the efficiency of green corrosion resistances as a coating material, pull-off test is performed to measure its adhesive strength.